Speaker design



Oct. 22 1963 I R. NAMON 3,107,746

SPEAKER DESIGN Filed April 29. 1960 2 Sheets-Sheet 1 IN VEN TOR. d A/amow, WW M Oc 22, 1 R. NAMON 3,107,746

SPEAKER DESIGN Filed April 29. 1960 2 Sheets-Sheet 2 A V aa {gig {All 4 l0 435 413 94 .544 J43 J43 J41 J40 INVENTOR. Emmi/Yam I bodying the invention; j 1 i United States Patent 3,107,746 SPEAKER DESIGN Richard Namon, 225 Lyon NE, Grand Rapids,Mich. FiledtApr. 29, 1960, Ser- No. 25,694 Claims. (Cl. 181 -32) This invention relates to transducers and in particular to high fidelity speakers.

In the known speaker constructions, increased fidelity has required the provision of complex'speaker structures and accurately coordinated and relatively expensive speaker enclosures. Further, the limited angle of sound dispersion produced by the known speakers has been a serious problem because of the highly directional characteristics thereof.

The present invention is concerned with a new and improved speaker eliminating the above discussed disadvantages of the known speakers. A prime feature of the present invention is, therefore, the provision of a new and improved transducer providing improved high fidelity operation.

Another feature of the invention is a provision of such a transducer comprising a flexible wall member having a mid-portion and edge portions on opposite sides of the mid-portion, first resilient means urging the edge portions toward each other and resultingly urging the mid-portion in a first direction transversely to a line between the edge portions, second resilient means urging the mid portion in a second direction opposite to the first direc tion and resultingly urging the edge portions away from each other to balance the urging of the first resilient means, means precluding movement of the edge portions in the second direction, and means reciprocating one of (a) the mid-portion inthe first and second directions and (b) an edge portion toward and from the other edge portion to flex correspondingly substantially the entire wall member. I

A further feature of the invention is the provision of such a transducer wherein the flexible wall member comprises a plate, the resilient means comprise spring elements, and the reciprocating means comprises a voice coil reciprocating the wallmember ,at sonic frequencies.

Still another feature of the invention is the provision of a new and improved transducer comprising a flexible wall member having a mid-portion and edge portions on opposite sides of the mid-portion, support means carryea ch other and resultingly urging the mid-portion in a first direct-ion transversely to a line between the edge pivotally reciprocating the support means to reciprocate the edge portions toward and from each other to'fiex correspondingly substantially the entire wall member. A yet further feature of the invention is the provision of a transducer comprising a flexible wall member hav-t ing a midportion and edge portionson opposite sides of the mid-portion; a pair .of linkshaving slots each slidably engaging a pivot anda pivotal connection atr-one of eachlink toan edge portion oflthe wall member for I ing the edge portions for pivotal movement about a pair v of spaced, parallel axes to move toward and away from urging the Wall member bodily transverselytofa lineg between 'the edge portions, and means longitudinally pr ating the linksto reciprocate the entire wall memberp't v. 1 7 a Other features and advantages of the invention" will be apparent from the following. description taken in vcon. ,7

nection with the accompanying 'drawingslwherein: FIGURE 1 is a front elevation of a transducer em- FIGURE 2 is avertical section (thereof taken substantially along the line 2-2 of FIGURE 1;:

spring blocks.

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FIGURE 3 isa transverse section thereof taken sub stantially. along the line 33- of FIGURE 1;

FIGURE 4 is a diagrammatic elevation of the wall member of the transducer; p p

FIGURE 5 is a diagrammatic plan View thereof;

FIGURE 6 is a diagrammatic plan View of another form of wall member for use therein;

FIGURE 7 is an elevation of still another form of Wall member for use therein;

FIGURE 8 is a transverse section taken substantially along the line 8-8 of FIGURE 7;

FIGURE 9 is a fragmentary plan view of another form of transducer embodying the invention;

FIGURE 10 is a fragmentary plan view of still an other form of transducer embodying the invention; and

FIGURE 11 is a fragmentary plan view of still another form of transducer embodying the invention.

In the exemplary embodiment of the invention as disclosed in FIGURES 1 through 5 of the drawings, a transducer generally designated 10 comprises a flexible plate wall member 11 having a mid-portion 12 and edge portions 13 and 14 disposed on opposite sides of the midportion 12. Herein the plate 11 is segmentally cylindrical whereby the mid-portion 12 is displaced transversely from a line A-A drawn between the edge portions 13 and 14 (see FIGURE 5). The edge portions 13 and 14 are slidably carried on a pairjof spaced supports 15 and 16, respectively, and are urged toward eachj other by a pair of resilient blocks 17 and 1'8, respectively, carried on a rigid frame 19.

As a result of the urging together 'of the edge por- 'tions 13 and 14 by the spring blocks 17 and 18, the midcompressed between a transverse support 21 carried by frame-19 and the mid-portion 12 of the plate 11. Herein, the characteristics of spring 20 are'coordinated .with the characteristics of the spring blocks 17 and 18 so that the plate 11 is urged to its unbiased segmentally cylindrical configuration against the balancing action of the Extending forwardly from the front face 2 2 of the plate mid-portion 12 is a voice coil 23 cooperating with amagnet 24, herein'a permanent magnet, carried on frame 19 to reciprocate the plate mid-portion 12 as a function of an alternating electrical current passed through the voice coil 23. The deflection of the plate mid-porv tion 12 causes )a corresponding movementof'the edge portions 13 and 14. toward or away from each other along the 1111s AA depending" on which direction along {line B- B mid-portion 12 has moved from the static v are urged apart against the balancing action of spring A position of FIGURE 2. Thus, when the mid-portion 12 is urged toward frame 1 9 the edgeportions 13 and 14 blocks 17 and 18. When the mid-portion 1 2 is urged away fromthe frame 19 against the action of spring 20 the edge portions. and 14 are urged toward each other along the IineA- A. Resultingly the entire plate member 11 is drivengat the frequency of the current in voice coil 23; wheie thecurrent alternates at a sonic frequency the'plate 11 functions as a high fidelity speaker diaphragm faithfully reproducing the electrical current as sound waves in the air surrounding the transducer.

As illustrated in FIGURE 5,,the angle 6: between the line A A and a line 25 drawn b etween an edge portion,

as edge: portion 14, and the mid portion 12-is-preferably 1 relatively. small, in the; range of approximately 5 or less. With such alsmall angle, the force relationship; between the forces acting on the mid-portion along the line B--B accurately linear.

and the forces acting on the edge portions along the line AA is given by the formula, forces (B- B) equal forces (AA) tangent Thus, illustratively where 5 equals 5 the forces B-B) need be only .087 times the forces (AA) for a balance thereof. Further, as a result of the small angle the movement of the edge portions 13 and 14, along the line AAcorresponding to a' givenmovement of the mid-portion 12 along the line B- B is relatively small.

In effect, the plate 11 vibrates in the direction of line AA as well as in the direction of the line B-B although to a somewhat lesser extent. The resultant direc tion of motion of the sound propagation is not in alignment with either of the lines AA or B'B but rather at an angle thereto. To utilize the sound producing effect of plate 11 most efiiciently, it is desirable to provide the forward surface thereof with a plurality of grooves having the faces thereof substantially perpendicular to the effective sound propagation direction. Thus, referring now to FIGURE 6, a modified form of plate 111 is shown to comprise a flexible wall member 111 generally similar to plate 11 but provided on the forward surface 122 thereof with a plurality of grooves generally designated 125 each havinga first surface 126 extending parallel to the direction of the resultant motion of the plate and a second surface 127 extending perpendicular thereto. As shown, the depth of grooves 125 may be approximately one half the thickness of the plate. By virtue of the grooves 125, plate 111 is capable of producing an extended frequency range of sound having a wide dispersion comparable to, andin some cases exceeding, the

dispersion characteristics of multi-speaker installations.

Referring now to FIGURES 7 and 8, another form of plate wall member 211 is shown to compiisea flat plate having a reinforcing bar 228 extending longitudinally along and rearwardly from the center of the rear surface 229 of the plate. Thus, reinforced, plate member 211 'may be ofsubstantial size such as six feet or longer in length.

Referring now to FIGURE 9, a portion of another modified form of transducer 310 is shown to comprise a flexible plate wall member 3-11 having end portions 313 and 314 slidably supported on supports 315 and '316 re spectively, and having secured thereto voice coils 3'30 and 331' respectively; Voice coil 330 cooperates with a suitable magnet 33-2 and voice coil 331 cooperates with a corresponding suitable magnet 333 to reciprocate the plate 311 by. applying reciprocating'opposing forces to the edge portions of the plate in the direction correspond-1 ing to the line A A of plate .11.. As the edge portions ,travel a distance especially less thanthe distance trav-' elled bythe mid-portion 312 of plate 311, extremely lin, ear 7 electromechanical. conversion is obtained.

While I ciprocation of the links 540 and 541 causes the entire plate 511 to be reciprocated correspondingly. I In each of the fragmentary showings of the different forms 'of transducer structures embodying the invention,

the vibration travelof thevoice coil 330 and 331 is not linear with respect to the balanced pos'itionfof the plate 311, the amplitude of the vibration of theplate in the direction of the maximum sound propagation will be While .a single voice coil associated with only one edge portion and a fixed mounting of the other edge portion may be used, an improved high fidelity output is obtained by the illustrated double voice. coil arrangement. i

In FIGURE 10, a portion of still another transducer 410 is illustrated'a's comprising a flexible wall member plate 411 having its edge portions 413 and 414 pivotally 1 secured by. means of"pins 4 34 and 435 respectively to a pair of corresponding pivot wheels '436 and 437. "Wheel only those elements differing from the elements of transducer 10 have been illustrated to disclose most clearly the different forms.

similar manner to produce an improved high fidelity sound reproduction.

Through use of the improved transducer structure herein disclosed, a high fidelity speaker is obtained without need for cooperating enclosure means. Extremely wide dispersion of the sound may be effected by producing the speakers disclosed herein in large sizes; illustra tively, the .plate may be six feet long by six inches high and may be driven by a suitable number of voice coils.

The inherent rigidity of the plate permits high power outputs with effectively minimized distortion over an extended frequency range, as for example 5-50,000 cycles per second.

Having described my invention in considerable detail, it is my intention that the invention be not limited by any of the details or description unless otherwise specified, but rather be construed broadly within the spirit and scope as set out in the accompanying claims.

1. A'transd-ucer comprising: a flexible plastehaving a mid-portion and edge portions on opposite sides of said mid-portion; first spring means urging said edge portions toward'ea'ch other and resultingly said mid-portion in a first direction transversely to a line between said edge portions; second spring means urg ng said mid-portion in a second direction oppositeto said first direction and resultingly said edge portions away from each other to balance the urging of said first resilient means, said first spring means being arranged to bias said edge portions toward each other independently of said second spring means;

.rigid means precluding movement of said edge" portions in said second direction, said plate mid portion being reciprocable in said firs-t and second directions and said plate edge portions being 'reciprocable toward and from each other; and a voice coil coupled .to said platefor reciprocating, at sonic frequencies, one of said portions to flex' correspondingly substantially the entire wall member.

7 2;. A transducer comprising: a flexible wall member having a mid-portion and edge portions on opptmite sides 7 of said mid-portion; first resilient means urging said edge portions toward each other and resultin-gly said mid-por- "tion in a first direction-transversely to a line between said edge portions; second resilient means urging said mid-portion in 'a, second direction opposite to said first direction and resultingly said edge portions away from each other to 436'pivots about an axis 438 parallel to an' axis-43W the plate 411. The wheels 436 and-437 arerotatively reciprocatedby suitabletransducer means (notshown) in correspondence with an electrical signal to"inove the about which wheel 437xpivots, the axes 438 and 439 ex tending parallelto the direction of sound propagation of plate edge portions 4131 and -414 alternately toward and I from each other in correspondence with the electrical the wall member.

balance the urging of said first resilient means, said first. spring means being arranged to bias said edge portions .to-

ward each other independently of said second spring means; rigid means precluding movement of said edge portions'in'said secondv direction, said wall member mid-por- .ti'on being reciprocable in said first and" second directions and said wall member edge portions being reciprocable toward and'from each other; and means coupled. to said wall member for reciprocating at sonic frequencies'one of correspondingly.substantially the eni said portions to flex Thus, except as otherwise noted, 'each of the dilferent structures functions in a generally The simplified construction permits the 7 speaker to be produced at extremely low cost and ,efrec tively eliminates maintenance problems.

3. A transducer comprising: a flexible wall member having a mid-portion and edge portions on opposite sides of said mid-portion; first resilient means urging said edge portions relatively toward each other and resultingly said mid-portion in a first direction transversely to a line between said edge p'ontions; econd resilient means urging said mid-portion in a second direction opposite to said first direction and resultingly said edge pontions away from each other to balance the urging of said firstresilient means, said first spring means being arranged to bias said edge portions toward each other independently of said second spring means; rigid means precluding movement of said edge portions in said second direction, said wall member mid-portion being reciprocable in said first and second directions and said wall member edge portions being reciprocable toward and from each other; and means coupled to said wall member for reciprocating one of said portions to flex correspondingly substantially the entire wall member.

6 4, The transducer of claim 3 wherein said second resilient means balances the urging of the first resilient means to dispose the wall member in its unflexed arrangement.

5. The transducer of claim 3 wherein at least one of said resilient means comprises a block of resilient material.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A TRANSDUCER COMPRISING: A FLEXIBLE PLATE HAVING A MID-PORTION AND EDGE PORTIONS ON OPPOSITE SIDES OF SAID MID-PORTION; FIRST SPRING MEANS URGING SAID EDGE PORTIONS TOWARD EACH OTHER AND RESULTINGLY SAID MID-PORTION IN A FIRST DIRECTION TRANSVERSELY TO A LINE BETWEEN SAID EDGE PORTIONS; SECOND SPRING MEANS URGING SAID MID-PORTION IN A SECOND DIRECTION OPPOSITE TO SAID FIRST DIRECTION AND RESULTINGLY SAID EDGE PORTIONS AWAY FROM EACH OTHER TO BALANCE THE URGING OF SAID FIRST RESILIENT MEANS, SAID FIRST SPRING MEANS BEING ARRANGED TO BIAS SAID EDGE PORTIONS TOWARD EACH OTHER INDEPENDENTLY OF SAID SECOND SPRING MEANS; RIGID MEANS PRECLUDING MOVEMENT OF SAID EDGE PORTIONS IN SAID SECOND DIRECTION, SAID PLATE MID-PORTION BEING RECIPROCABLE IN SAID FIRST AND SECOND DIRECTIONS AND SAID PLATE EDGE PORTIONS BEING RECIPROCABLE TOWWARD AND FROM EACH OTHER; AND A VOICE COIL COUPLED TO SAID PLATE FOR RECIPROCATING, AT SONIC FREQUENCIES, ONE OF SAID PORTIONS TO FLEX CORRESPONDINGLY SUBSTANTIALLY THE ENTIRE WALL MEMBER. 